A Beginner's Guide to Understanding Pigeonhole Sort: An Example in JavaScript.

Pigeonhole sort is a sorting algorithm that is a variation of the counting sort algorithm. It is used to sort a small range of integers, where the range of integers is known in advance. It works by creating "pigeonholes" for each element in the range, and then counting the number of times each element appears in the input array. The sorted output is generated by iterating through the pigeonholes and outputting the elements in the order they appear.

The example of Pigeonhole Sort in javascript starts by finding the minimum and maximum values in the input array. It then uses those values to calculate the range of integers. Then it creates an array of pigeonholes with the length of the range, and fills it with zeroes.

The algorithm then enters a for loop that iterates through the input array and increments the count in the corresponding pigeonhole for each element. This step is counting the number of times each element appears in the input array.

Finally, the algorithm iterates through the pigeonholes and outputs the elements in the order they appear. This step is generating the sorted output.

The time complexity of Pigeonhole sort is O(n + r) where n is the number of elements in the input array and r is the range of integers. This makes it efficient for small ranges of integers, but not suitable for large ranges or unknown ranges as it requires additional memory space to create the pigeonholes.

Here is an example of the Pigeonhole sort algorithm implemented in JavaScript:

function pigeonholeSort(arr) { 
var min = Math.min(...arr);
var max = Math.max(...arr);
var range = max - min + 1;
var pigeonholes = new Array(range);
 pigeonholes.fill(0);
 for (var i = 0; i < arr.length; i++) {
 pigeonholes[arr[i] - min]++;
 }
var sorted = [];
 for (var i = 0; i < pigeonholes.length; i++) { 
 for (var j = 0; j < pigeonholes[i]; j++) { 
 sorted.push(i + min);
 } 
 } 
 return sorted; 
} 
 console.log(pigeonholeSort([5, 3, 8, 4, 1, 2])); // [1, 2, 3, 4, 5, 8]

In this example, the algorithm first finds the minimum and maximum values in the input array and uses them to calculate the range of integers. It then creates an array of pigeonholes with the length of the range, and fills it with zeroes.

The algorithm then enters a for loop that iterates through the input array and increments the count in the corresponding pigeonhole for each element.

Finally, the algorithm iterates through the pigeonholes and outputs the elements in the order they appear.

The time complexity of Pigeonhole sort is O(n + r) where n is the number of elements in the input array and r is the range of integers. This makes it efficient for small ranges of integers, but not suitable for large ranges or unknown ranges.